Test Data Manager

My file have about 17 different layout, we can distinct each of them by the value of the first field (Layout 01 will have 01 in the first 2 chars)

I've registered an object in Datamaker using the option "File Definition from G-T Excel file". This created 17 tables in my datapool, but i can't find a way to import my file in the datapool.

Is there a built-in way to import a positional flat file to a Datapool using TDM Portal or Datamaker?

Yes, you can import the sample file using either datamaker or TDM Portal.

To do this using Datamaker, just right click on the data pool and click on "Import External File Data" and follow the prompts. 

You can refer the below link to do the same in TDM Portal.

G-T Excel File Type - CA Test Data Manager - 4.6 - CA Technologies Documentation